Religion when applied properly is about enlightenment.

Most religions that survived helped the societies they integrated into... Not sure how the Thugee cult survived so long, but they weren't particularly big in comparison.

Having a common framework and belief system creates a more powerful society that can survive better. The meme sets that developed meant that religious societies like are much like gene based animals they compete, create, and share resources.

IMDHO religions changed overtime to reflect the societies they were in. Changing from animalistic to animal-human hybrids to pantheons to families, paired entities and finally a single father figure. These changes were about the way we interacted with our environment moving from nomadic, to seasonal farming to city dwellers. No big conspiracy just humans trying to make sense of their surroundings.